Putti Thomas C, Teh Ming, Lee Yoke S
Department of Pathology, National University of Singapore, Republic of Singapore.
Mod Pathol. 2004 Apr;17(4):468-75. doi: 10.1038/modpathol.3800063.
Distinguishing keratoacanthoma from squamous cell carcinoma is a persistent issue in pathology practice. Solitary keratoacanthoma is a self-limiting lesion as opposed to rather aggressive clinical behavior of squamous cell carcinoma. Several markers were studied to understand their biology and to separate these two lesions on a firm basis, but without much success. In this study, we plan to utilize recent markers such as telomerase activity and cyclooxygenase-2 (COX-2) along with more established marker p53 in understanding the biologic differences between keratoacanthoma and squamous cell carcinoma. We studied 17 well to moderately differentiated squamous cell carcinoma and 24 early proliferative phase keratoacanthoma by immunohistochemistry for the expression of p53 protein, COX-2 and telomerase activity. Higher telomerase activity was found in 11/17 squamous cell carcinoma (65%) compared to 4/24 (17%) of keratoacanthoma. Similarly, stronger expression of p53 and COX-2 was detected in 12 (71%) and 11 (65%) cases of squamous cell carcinoma compared to 2 (8%) and 2 (8%) cases of keratoacanthoma respectively. A highly significant 'P' value was obtained for telomerase activity (0.001), p53 (0.000), and COX-2 (0.001). Telomerase activity, COX-2, and p53 expression provide evidence that keratoacanthoma and squamous cell carcinoma are indeed distinct entities and also help in discriminating these two lesions, which closely resemble each other on conventional morphology. Although these markers present new insights into the biologic variation of keratoacanthoma and squamous cell carcinoma, they are of limited value for routine application in histological distinction of these two lesions. The differential expression of markers also explains the sustained proliferation observed in squamous cell carcinoma, compared to a shorter lifespan and involution in keratoacanthoma.
在病理学实践中，区分角化棘皮瘤和鳞状细胞癌一直是个难题。孤立性角化棘皮瘤是一种自限性病变，与鳞状细胞癌具有较强侵袭性的临床行为相反。人们研究了多种标志物以了解它们的生物学特性，并在可靠的基础上区分这两种病变，但成效不大。在本研究中，我们计划利用端粒酶活性和环氧化酶-2（COX-2）等最新标志物以及更成熟的标志物p53，来了解角化棘皮瘤和鳞状细胞癌之间的生物学差异。我们通过免疫组织化学研究了17例高分化至中分化鳞状细胞癌和24例早期增殖期角化棘皮瘤中p53蛋白、COX-2的表达及端粒酶活性。在17例鳞状细胞癌中有11例（65%）端粒酶活性较高，而在24例角化棘皮瘤中只有4例（17%）。同样，在鳞状细胞癌中，分别有12例（71%）和11例（65%）检测到p53和COX-2的更强表达，而在角化棘皮瘤中分别只有2例（8%）和2例（8%）。端粒酶活性（P = 0.001）、p53（P = 0.000）和COX-2（P = 0.001）均获得了高度显著的“P”值。端粒酶活性、COX-2和p53表达证明角化棘皮瘤和鳞状细胞癌确实是不同的实体，也有助于区分这两种在传统形态学上极为相似的病变。尽管这些标志物为角化棘皮瘤和鳞状细胞癌的生物学差异提供了新的见解，但它们在这两种病变组织学区分的常规应用中价值有限。标志物的差异表达也解释了与角化棘皮瘤较短的病程和 involution 相比，鳞状细胞癌中观察到的持续增殖现象。（注：原文中 involution 这个词在医学语境中可能有“退化”等意思，这里结合语境翻译为“病程”较合适，但感觉原文此处表达似乎不太准确完整。）
